Fuel Performance Lead

Help Us Prove a New Standard in Nuclear Fuel

Are you a technically sharp, self-driven engineer or scientist who understands how nuclear fuel really behaves - and how to prove it with credible models? Join Blykalla and lead the fuel development and qualification effort that underpins the use of a novel nuclear fuel in an advanced reactor. This role puts you at the center of predicting, validating, and defending fuel behaviour for the western world's first lead-cooled SMR. You'll own the delivery of the fuel qualification programme, and strongly influence the development of models and codes that allow for producing regulator-ready evidence to understand our fuel performance.

What we do at Blykalla At Blykalla

we are developing the next generation of nuclear technology with our Advanced Small Modular Reactor (SMR), based on uranium nitride fuel and a compact, lead-cooled design. As Sweden's only SMR developer, we are on a mission to decarbonize heavy industry and other energy-intensive sectors and deliver safe, scalable, and sustainable energy.

What you'll get to do Your mission is to ensure that we can predict, explain and justify fuel behaviour with confidence, using validated models, defensible assumptions and traceable data. Build & evolve fuel performance models

• Take ownership of the development, extension, and adaption of fuel performance models for a lead-cooled fast-spectrum operation, with a focus on physical mechanisms rather than black-box use.

• Lead the benchmarking of models against multiple fuel types (including nitride, oxide and metallic fuels) and fuel performance codes, to support comparison, validation, and fallback options. • Understand and improve model behaviour by analysing why models work, where they break down, and what must be changed for lead-cooled fast spectrum operation.

• Work closely with experimental and design teams to specify experimental testing (in- and out-of-pile) and examinations that generate data relevant for model validation or development. Shape data, experiments, and model credibility

• Define what experimental and operational data are needed to support, challenge, and improve fuel performance models

• Work closely with experimental and design teams to specify irradiation tests and pre- and post-irradiation examinations that generate data relevant for model validation or development

• Integrate data from experiments, literature, and historical programmes to calibrate models, assess validity ranges, and reduce key uncertainties

• Contribute to cross-disciplinary activities between reactor physics, thermal hydraulics, materials, backend, safety and licensing to ensure design coherence, manufacturability, and regulatory compliance. Align modelling with fuel qualification, licensing and industrialisation

• In collaboration with the Head of Fuel and wider fuel team, drive forward the company's advanced fuel qualification and update our plans for how the company will meet them.

• Define, maintain and own the modelling basis used in fuel qualification, including scope, gaps, assumptions, acceptance criteria, and regulatory expectations

• Coordinate with international labs and irradiation facilities to secure the knowledge and services (irradiation, PIE) needed to reach qualification and licensing goals.

• Ensure Blykalla is pro-active in interfacing with regulatory bodies and relevant programs that support advanced fuel qualification/performance modelling (including, but not limited to: SSM, DOE/NRC and IAEA).

• Contribute to the establishment of modelling workflows, documentation, and quality practices that ensure traceability, reproducibility, and regulatory readiness Fuel Design & Development

• With the Head of Fuel and Head of Nuclear Safety, coordinate cross-disciplinary integration of the fuel design between nuclear design, thermal-hydraulics, materials group, fuel experimental and modelling teams to ensure design coherence, consistent modelling assumptions, manufacturability, and regulatory compliance." Technical leadership

• With the Head of Fuel, support the transfer of knowledge and development of the next generation of "subject matter experts" across both fuel performance authorities or cross-disciplinary technical leadership.

• Provide technical mentorship to early career individuals, disseminating your experience and knowledge. Experience & Qualifications

• At least 15-years post-degree experience in nuclear fuel modelling, development and/or qualification.

• Modelling and simulation experience covering code/model modification, development or critical assessment rather than "black-box" use

• Degree, ideally PhD in nuclear engineering, physics, chemistry or a closely related field

• Experience defining and integrating experimental data from irradiation tests, post-irradiation examinations, literature, or historical programmes to support and improve modelling and accelerate fuel qualification

• Ability to define what data and experiments are needed to support model credibility and uncertainty reduction, and to work effectively with experimental and qualification teams

• Demonstrated ability to understand fuel behaviour at the mechanism level and to diagnose why models work, where they fail, and how they must be improved

• Hands-on experience with fuel performance codes such as TRANSURANUS, FRAPCON/FRAPTRAN, BISON, or similar tools, including extending, adapting, or validating models

• Understanding of how modelling contributes to fuel qualification, safety arguments, and regulatory submissions

• Ability to communicate and defend modelling assumptions, limitations, and results in technical discussions with regulators, authorities, and partners

• Fluency in English; Swedish is an advantage

• Willingness to travel within Europe, North America and occasionally beyond

• Eligibility to work with nuclear materials in Sweden Location The position is based in Stockholm. Travel to partner sites and research facilities will be part of the role.